最新刊期
卷 62 ， 期 2 ， 2026
- 摘要：For achieving the health statu prediction of circuit breaker, a method for health assessment and prediction of circuit breaker based on acoustical signal analysis is proposed. This method adopts the empirical mode decomposition (EMD) algorithm to decompose the circuit breaker’s opening scoustical signal to obtain multiple intrinsic mode functions (IMF) component. The time-domain feature indicators of these IMFs are then fused using kernel principal component analysis (KPCA) to establish a comprehensive health indicator (HI) of the circuti breaker so to characterize the operational health condition of the circuit breaker. Additionally, a one-dimensional convolutional neural network (1D-CNN) model is set up to predict the health status of the circuit breaker. Finally, the experimental data from a 12 kV indoor vacuum circuit breaker is taken as an example. The result shows that the HI curve of the circuit breaker constructed by the method exhibits good monotonicity and can perform accurate ssessment and prediction on the health status of the circuit breaker.关键词：circuit breaker;acoustical signal;health indicator;convolutional neural network;health assessment and prediction32|11|0更新时间：2026-03-16
- 摘要：The variation of vibration signal of GIS equipment can reflect the mechanical condition inside the equipment. For improving the prediction accuracy of vibration signal characteristics of GIS equipment, in this paper a combined group measurement model based on decomposition-forecasting-reconstruction is proposed. First, based on historical vibration signals of GIS, vibration characteristic parameters are extracted in frequency domain by Fourier transform. Then, in order to eliminate as much as possible the influence due to the non-stationary characteristics of the vibration characteristic parameter sequence, the normalized sequence is decomposed by the variational mode decomposition (VMD) optimized by particle swarm optimization (PSO). Finally, the time convolution network (TCN) is used to predict a set of stationary modal components obtained by decomposition. The experimental results show that the root mean square error and the average absolute percentage error of the combined prediction model based onPSO-VMD-TCNproposed in this paper are 1.79% and 0.13%, respectively, which are superior to other methods in prediction accuracy and are conducive to the early fault diagnosis of GIS equipment.关键词：GIS equipment;non-stationary characteristic;prediction model;temporal convolutional network;vibroacoustic characteristics26|6|0更新时间：2026-03-16
- 摘要：In order to widely apply vacuum circuit breaker to high voltage level, the interruption of long gap and high current arc in vacuum has always been a hot issue in the industry. The long gap and high current arc interruption technology in vacuum has put forward special requirements for the opening motion of contact. It is such threestage motion characteristic as fast first, slow later and fast again. In this paper, a mid-course buffer device is designed based on the structure of the middle spring. It can realize the effect of the middle deceleration and the late acceleration simultaneously. The feasibility of the device is verified by simulation calculation and, at the same time, the influence of different device parameters on the opening motion curve is analyzed by simulation. The final design parameters can achieve the requirements of three-stage opening motion which is porposed in the paper. The average opening speed of the first 30 mm reaches 3.63 m/s, the average opening speed of 30-45 mm reaches 1.52 m/s, and the average opening speed of 45-60 mm reaches 3.56 m/s.关键词：high voltage vacuum circuit breaker;short-circuit current breaking;opening motion coordination;three-stage opening motion characteristics;mid-course buffer device36|8|0更新时间：2026-03-16
- 摘要：As for such common fault as opening immediately after closing of spring operating mechanism for circuit breaker, in this paper an opening immediately after closing of circuit breaker based on the image feature point tracking is proposed. Firstly, the main analysis direction of the fault of opening immediately after closing is determined through the analysis of the transmission process of the spring operating mechanism. Then, based on the high-speed camera data acquisition platform, the complete process of the closing and opening moments, as well as the transmission of the four-stage opening levers in the spring operating mechanism, are recorded, and the bounce amplitude analysis method based on image feature point tracking is proposed. The movement track of the four-stage opening lever is accurately tracked through the feature point, and the deflection angle parameter is introduced to accurately quantify the bounce amplitude of the four-stage opening lever. Finally, through the analysis of the deflection angle waveform, the main cause of the opening immediately after closing of the circuit breaker is determined. The analysis conclusion of the fault is fully demonstrated by the experimental verification part of the paper, and the experience of this fault analysis can provide useful reference for the research and treatment of the subsequent opening immediately after closing.关键词：circuit breaker;opening immediately after closing;high speed camera;four-stage opening lever;deflection angle16|5|0更新时间：2026-03-16
- 摘要：The closing resistor plays an important role in suppressing the overvoltage and closing inrush current of filter bank circuit breakers. However, with the increase in voltage, the failure rate of the closing resistor in 800 kV filter circuit breakers significantly rises.Currently, multi-field coupling simulations for the working environment of the closing resistor are insufficient, and corresponding improvement measures have not been verified. In this paper various possible failure causes of closing resistor in filter circuit breakers are simulated and analyzed. The corresponding improvement solutions are proposed and the improvement effectiveness is verified by simulation. The results show that under normal conditions the closing resitor is normal in electric field distribution and stable in operation. However, in case of abnormal conditions, local temperatures rise rapidly, potentially leading to concentrated thermal stress and affecting its performance. The common faults include the attachment of metal foreign objects to the surface of the resistor, wek coaxiality of the resistor disc and weak contact at the end faces. To address these issues, several optimization measures are proposed, namely, adding aluminum sheets between resistor disc to improve weak contact at the contact surfaces;adding aluminum blocks to the end resistor blocks to reduce stress concentration at the ends;and increasing the external surface diameter of insulation support and the outer sheath of the closing resistor stack to enhance the coaxiality of the resistor disc, thereby reducing electric field distortion and improving overall protection. Simulation results show that these optimization measures significantly enhance the performance of the closing resistor , reduce temperature rise and thermal stress and improve its safety and reliability, which are of significant importance for the simulation analysis and optimization design of closing resistor.关键词：closing resistor;thermal stress;filter circuit breaker18|5|0更新时间：2026-03-16
- 摘要：Fault or defect knowledge graphs of power equipment could effectively improve the intelligent and automatic level of operation and maintenance of the equipment and, horever, the extractions of text and relations is crucial to the construction of the graph. However, in fault or defect text, the entity relationship triples often overlap or embedded each other, resulting in not only difficult treatment by traditional method, but also accompanying such issues as error transmission and redundant entity inference. As for these issues, in this paper a joint extraction method based on relation-oriented with Bi-LSTM is proposed.In this method, the triplet extraction task is modeled as the process of mapping the head entity to the tail entity under different relationship types. First, the head entity is extracted and then the corresponding tail of each type of relationship is marked for the identified entity, thus effectively mitigating the issues related to overlapping and nesting triples as well as redundant entity-relationship inference.The experiments show that the proposed method is more robust than the baseline model when triples overlap or nest occurring at different degrees, the F1 value is improved by 8.57%to 25.19%, which verifies both effectiveness and feasibility of the proposed model.关键词：power equipment;fault or defect text;knowledge graph;knowledge extraction;deep learning10|3|0更新时间：2026-03-16
- 摘要：110 kV modular substation adopts a modular construction approach, featuring standardization, factory prefabrication and intensive design, making it the preferred construction model for smart substations.110 kV modular substation in operation is affected by the difference of climate environment in different regions, and the problem of heat accumulation and condensation of electrical equipment is existed, which affect seriously both life, safe and stable operation of the electrical equipment. In this paper, the heat generation characteristics of 110-A2-6 modular substations and their electrical equipment in Jiangsu province are taken as the research subject. The heat generation characteristics of such main electrical equipment as transformers, capacitors, switchgear, GIS are modelled and analyzed, and the heat generation patterns of the electrical equipment in modular substations are obtained. Finally, the method of placing loop control sensors is introduced in the 110 kV modular substation, and the measured data is matched with the heat generation model, thus providing a reference basis for the improvement of the heat and humidity environment in the modular substation.关键词：modular substation;electrical equipment;heat generation characteristics;hot and humidity environment12|2|0更新时间：2026-03-16
- 摘要：Dissolved gas analysis in oil is the main method of early fault diagnosis of transformer. Accurate prediction of the future characteristic gas concentration contributes to gain operation status of transformer in advance. Therefore, the prediction model of dissolved gas concentration in transformer oil based on multistage feature extraction andIHHO-KELMis proposed. Firstly, the dissolved gas concentration data is decomposed into multiple subsequences by complete ensemble empirical mode decomposition with adaptive noise, and the subsequences are further denoised by singular spectrum analysis to reduce its non-stationarity. Then, kernel based extreme learning machine is set up to predict each subsequence. After that, the prediction result of each subsequence is superimposed into the final prediction result of oil dissolved gas concentration. Meanwhile, the improved Harris hawk optimization is used to optimize the hyper-parameter of kernel based extreme learning machine. Finally, it is shown by the calculation example that the proposed model has better prediction performance, which can better track the variation trend of dissolved gas concentration in transformer oil.关键词：prediction of dissolved gas concentration in oil;complete ensemble empirical mode decomposition with adaptive noise;singular spectrum analysis;improved harris hawk optimization11|3|0更新时间：2026-03-16
- 摘要：Most of the existing research on the seismic performance of transformer is focused on the transformers with fixed connection to the foundation.While the seismic performance analysis of free-standing transformer is less. In this paper, a 500 kV free-standing transformer for a project is selected and a refined modeling for the transformer is carried out. The seismic response data of the key position of the transformer is obtained by using the seismic performance analysis method considering the coupling loop of the transformer outlet. The vulnerable parts that may be damaged in the earthquake is analyzed, and the overall horizontal sliding of the transformer is analyzed. The results show that the first ten natural vibration modes of the transformer are the first order transnational or torsional modes of componens such as the high-voltage bushing-turret system and the oil conservator, and the natural vibration frequency is in the range of 1-10 Hz, which coincides with the excellent frequency of ground motion. The stress level at variable section of GIS bushing and the root of the oil conservator support the transformer is high under seismic condition, has the risk that the peak stress exceeding the material ultimate stress and is the weak positions of the transformer. In seismic cases, the free-standing transformer will produce a certain horizontal slip, resulting in the overall displacement of the transformer, and producing a certain tensile stress in the structure of the high-voltage outgoing terminal, which will increase the stress level and aggravate the possibility of structural damage.关键词：free-standing transformer;finite element simulation;modal analysis;seismic response;horizontal slip11|3|0更新时间：2026-03-16
- 摘要：Noise reduction in transformer proper is a key issue that both power grid companies and manufacturers focus on addressing. The main source of transformer noise is from the core vibration, while the vibration and noise at the core joints shall also not be ignored. In this paper, through modeling the single silicon steel at the transformer joint area, the different lapping forms, lapping width and the number of laminations at each stage are simulated and calculated, the influence of Lorentz force on the core vibration due to the magnetic flux passing through the joint area is analyzed, and the method of vibration reduction and noise reduction based on the joint form is proposed from the microscopic perspective. The influence of Lorentz force on vibration noise is further verified through clamping force test, which provides effective theoretical support for noise reduction of transformer.关键词：joint;core;step lap joint;Lorentz force;vibration;noise10|4|0更新时间：2026-03-16
- 摘要：Pressure relief valves are commonly installed in transformers as pressure protection device and their design function is, in case of rise of internal pressure of transformer, to mitigate internal overpressure by releasing insulating oil, thereby protecting the safety of the equipment structure. However, in recent years, explosion and fire accidents triggered by internal arcing faults in oil-immersed transformers have become more frequently and the pressure relief valves did not play the effective protective role and their pressure relief protection has been questioned by the industry. For assessing the protection effect of the pressure relief valves in case of arcing fault inside the oil immersed oil transformer, in this paper the calculation model of internal fault oil pressure of transformer is set up and the effect of various fault depths on pressure relief effect of pressure relief valves at different fault depths is simulated and studied.The simulation result shows that under the same arc energy and different depths of fault conditions, the switcing-on time of the pressure relief valves is obviously different. When the fault occurs in the shallow position near the top cover of transformer, the pressure relief valves can respond quickly.Under the arc energy of 2 MJ, the pressure relief effect of the pressure relief valves at the the central point of the top cover can reach 13.1%. While, in case of the fault in the deep position, the fault point is far from the installation place of the pressure relief valves, causing the operation of the pressure relief valves to be slower and the pressure relief effect of the pressure relief valves is reduced to 9.3%.The study in this paper can provide theoretical reference for the optimization of design and layout scheme of pressure relief valves of transformer.关键词：oil-immersed transformer;pressure relief valves;pressure relief effect;internal arcing fault;numerical simulation11|5|0更新时间：2026-03-16
- 摘要：Dry-type DC capacitors, as a key equipment in VSC-HVDC transmission system, are used widely in such important applications as filtering and voltage support. It is of great significance to ensure the long-term, safe and reliable operation of dry-type DC capacitors. In case of external short-circuit fault in the capacitor, the rapidly increased short-circuit curren will flow through the internal busbar and result in great electrodynamic force, which easily cause structural failure of the capacitor. In order to study the issue of capacitor withstanding short-circuit electrodynamic force under short-circuit current impact, in this paper a type of dry-type DC capacitor is taken as the research object, the short-circuit electrodynamic force distribution, deformation as well as stress of the capacitor under shortcircuit conditions are calculated and analyzed based on calculation method of magnetic-structure field coupling. The results show that in case of external short-circuit fault, the maximum short circuit electrodynamic force of the capacitor reaches 10.8 kN. The deformation of the capacitor mainly occurs on the leading-out copper busbar and its surrounding areas, and the deformation approaching the middle part of the busbar is larger. The leading-out terminal shows an obvious downward squeezing trend. The research results in this paper provide theoretical reference for mechanical strength check and structural optimization design of capacitor.关键词：dry-type DC capacitor;magnetic-structure field coupling;short-circuit electrodynamic force;deformation of structure10|2|0更新时间：2026-03-16
- 摘要：Capacitor voltage transformers (CVT) are used widely in EHV/UHV power systems. The failure of CVT not only affects the accuracy and reliability of electric energy measurement but also the stable and safe operation of power grid. In this paper the CVT capacitor unit with the highest fault rate is taken as the research object. By making the sample suitable for reflecting the electrode defects of CVT capacitor core, the corresponding experimental platform is set up to perform the breakdown experiment under different electric field conditions and analyze the breakdown point distribution of the sample. Moreover, the damage mechanism of film paper insulation under power frequency voltage, positive and negative polarity lightning impulse voltage and AC superposition impulse composite electric field is studied. The experimental results show that the edge defect of aluminum foil electrode of CVT capacitor core is the main cause for the insulation damage of film paper, and the types and changes of electrode defects determine the spatial distribution of breakdown points. However, the difference in the‘trap’effect of polypropylene film on positive and negative space charges will lead to transformation of the dominant type of breakdown point under different superposition amplitude and phase.关键词：capacitor voltage transformer (CVT);film-paper insulation;AC superposition impulse composite electric field;electrode edge;breakdown characteristics10|5|0更新时间：2026-03-16
- 摘要：The heat dissipation of reactors in DC field is a hot issue affecting the development of UHV technology. For solving such issues in traditional problems as large energy consumption, uneven cooling and dust flying associated with traditional air supply methods and starting from the perspective of the characteristics of reactor as well as indoor environment regulation and control, a novel radiation plate for cooling method is proposed in this paper. A ±800 kV UHV DC field in Guangzhou is taken as an example, the structual optimization design of the radiation plate of the reactor is performed and the Fluent software is used to simulate and study the cooling effect of radiation plate placement position on the UHV DC filed. The study shows that the effect is more significant with the radiation plate within 500 mm. The cooling effect of the internal radiation plate to the reactor is better than that of external radiation plate. However, the combined effect of the internal and external placement of radiation plate is not significant.关键词：UHV DC field;reactor;thermal environment;radiation cooling10|3|0更新时间：2026-03-16
- 摘要：With the continuous increase of wind power penetration, the low voltage ride-through behavior of the wind fan affects the safe and stable operation of power grid, making it of practical significance to ensure that the fan remains connected during faults without tripping. The grid-connected mathematical model of direct drive permanent magnet fan is set up, and the analytical expressions of voltage, current, power and other related electrical quantities in the low-voltage ride-through process of direct drive fan are derived. A new reactive power compensation scheme is proposed, which increases the reactive power generation and is beneficial to the recovery of system voltage. Finally, MATLAB simulation is used to verify the correctness of theoretical research and effectiveness of the new reactive power compensation scheme.关键词：direct drive fans;low voltage ride-through;electrical quantities variation;theoretical equation;reactive power compensation9|4|0更新时间：2026-03-16
- 摘要：The health condition of insulating spacer has important influence on the construction and operation of power grid. In this paper, the finite element simulation of ultrasonic guided wave detection of the insulating spacer defect is carried out to study the feasibility of ultrasonic guided wave detection of the insulating spacer under various defect cases. It is foundthat when the defect size is small and the distance is far from the excitation point, and the angle of the vertical plane where the offset excitation point and the receiving point are located is large, the signal attenuation rate is small and the detection effect is not ideal. For achieving better detection effect, an optimal setting scheme of ultrasonic guided wave excitation points is proposed in this paper. In addition to the commonly used excitation points, a set of excitation points are added on the insulating spacer surface. As for the defects with weak detection effect at the commonly used excitation points, the excitation position on the insulating spacer surface is used for detection. The experimental platform is set up to verify the scheme. The received signal attenuation rate of the optimized scheme will be increased by about 10% and the detection effect will be significantly improved. The optimization scheme can provide reference for the defect detection of insulating spacer based on ultrasonic guided wave.关键词：insulating spacer;defect detection;ultrasonic guided wave;excitation point10|3|0更新时间：2026-03-16
- 摘要：The natural environment in western regions of China is complex, leading to a numerous instances of damage to the catenary porcelian insulators due to both human and non-human factors. For studying the influence of the damaged shed on safe operation of the catenary systems, the simulation model of the catenary oblique swage aram insulators simulation with different damage magnitude, different damage locations, combination of two damage positions and different surface conditions is set up, and its electric field distribution characteristics are analyzed using finite element software. The simulation results show that the larger the damage radius of the damaged shed, the higher the surface electric field intensity at the damaged position and, compared with intact insulators, the electric field intensity is increased by 30.11% with the damaged radius reaching 30 mm. In case of same damaged radius and the shed damage at high-voltage side, the increase amplitude of the eielctric field intensity is the maximum.While, in case of damage at two positions, the larger the relative positions, the smaller the increase amplitue of electric field intensity.When the damage is between the high voltage and low voltage ends and the inclination angle is 0°, the electric field intensity is increased by 47.31%.In case of water accumulation or surface covered with water at the damaged insulator, the electric field intensity is increased significantly and, compared with the intact insulator, the electric field intensity is increased by 129.57% and 260.22%, respectively. The study findings can provide valuable data support for the operation and maintenance of catenary catenary oblique swage aram insulators.关键词：catenary system;oblique wrist arm insulator;shed damage;finite element;electric field distribution8|3|0更新时间：2026-03-16
- 摘要：Power cables are composed of the cable body and cable joints, and the temperature rise inside the cable joints is a key factor affecting the current carrying capacity of power cable lines. In view of such issues as large dispersion of cable joint material parameters and unclear heat flow diffusion, in this paper a cable joint hot spot temperature inversion identification method based on main heat flow analysis is proposed to accurately identify the hot spot temperature inside the joint. Firstly, a finite element simulation calculation model for 10 kV three core cables and joints is set up to obtain the temperature field distribution. Then, a thermal path model of the cable body is set up by analyzing the heat flow diffusion law of cable joints. The orthogonal test method is used to design training and testing samples and determine two conductor characteristic temperature points at distances of 0.1 m and 2.0 m from the end of the joint, thus, a joint hot spot temperature combination inversion method for radial and axial inversion of the body is constructed. Finally, a multi condition temperature rise test platform for cables is set up. The test results shows that under different loads, external wind speeds and ambient temperatures the maximum difference between the simulated and experimental values of the hot spot temperature is 2.29 K, and the maximum error between the inversion value of the hot spot temperature and the experimental value is 3.92 K, which provide a reference for the thermal fault monitor ing method of cable joint.关键词：three core cable;intermediate joint;main heat flow;hot spot temperature;axial inversion;radial inversion;inversion identification;test verification8|3|0更新时间：2026-03-16
- 摘要：Accurattely and rapidly calculating the transient core temperature rise in buried power cables under emergency load and transferred load conditions is of great significance for improving the refined management level of dynamic current-carrying capacity of power cable. First, a transfer matrix is obtained by using the finite element steadystate analysis, while finite element transient analysis is used to obtain self-heating transient temperature rise data for an single cable and mutual-heating transient temperature rise data for the rest cables. Then, a composite transient thermal circuit model is constructed.The self-heating thermal model of the loaded cable consists of two-branch of thermal resistance-thermal capacitance network, while the mutual-heating thermal circuit model of adjacent cables comprieses a single-branch of thermal resistance-thermal capacitance network, and a Runge-Kutta method is presented to solve this composite transient thermal circuit model. Finally, the finite element simulation results are taken as a benchmark, a genetic algorithm is applied to optimize and solve for the thermal resistance and thermal capacitance parameters of the composite thermal circuit model. For a specific case study, the transfer matrix is used to obtain the steady-state temperature rise of each cable. Thermal-electrical coupling is achieved by updating losses at each time step, and the composite thermal circuit model is then employed to calculate the dynamic current carrying capacity of any individual cable. It is shown by the comparison with the finite element calculation results that the proposed method in this paper has high accuracy and is suitable for engineering applications involving operational management of emergency and load-transfer currents in directly buried cables.关键词：burried power cables;composite transient thermal circuit;transient core temperature rise;dynamic current-carrying capacity;Runga-Kutta method;transfer matrix;electrical-thermal coupling8|3|0更新时间：2026-03-16
- 摘要：Corrugated aluminum sheath is used widely in high-voltage cross-linked polyethylene (XLPE) insulated cable due to its excellent bending performance. However, in recent years, there have been many cable ablation failures from the buffer layer, which will seriously develop to the insulation shield layer and even the insulation layer. In this paper the ablation mechanism of insulation shield due to radial electric field is studied. The ablation mechanism of insulation shield is deduced by simulating the discharge of insulation shield in different gaps. The experimental results show that the buffer layer will develop inward after ablation, resulting in insulation shield ablation. The breakdown, in the case of spacing, is the air breakdown between the buffer layer and the insulation shield sample as well as the electrode. While, in the case of no spacing, the breakdown is the insulation shield ablation caused by the electrode directly penetrating the buffer layer. The ablation of the buffer layer will greatly affect the electrical performance of the insulation shield. It is therefore necessary to focus on the ablation faults at the contact point between the aluminum sheath and the buffer layer, which is conducive to preventing cable failure and ensuring safe and stable operation of power grid.关键词：high voltage XLPE insulated cable;insulation shield ablation;radial electric field;simulated discharge experiment9|3|0更新时间：2026-03-16
- 摘要：The roughness coefficient m of the conductor surface is one of the key factors affecting the estimation of corona inception field strength. Under the rainfall conditions, raindrops are easily attached to the surface of highvoltage direct current transmission lines, and the surface condition of the conductor has changed. The change in the surface condition of the conductors directly affects the roughness coefficient m in the Peek formula, resulting in a significant error between the estimated corona inception field strength and the actual value. Under present rainfall conditions, there is no unified standard for the value of roughness coefficient m. In this paper the deformation coefficient W and distribution coefficient f are introduced to characterize the influence of raindrop magnitude and distribution density on the corona inception field strength. The correlation relationship among the deformation coefficient, distribution coefficient and roughness coefficient is set up by utilizing the variation law between the corona inception field strength and those two factors. The expression of roughness coefficient m under different rainfall levels is obtained, and the Peek formula is thus modified. The feasibility of the scheme is verified by establishing a calculation model for the high-voltage DC conductor with attached raindrops and comparing it with the simulated field strength values of the corona cage. The results show that the error between the calculated electric field strength of the corona cage and the field strength obtained based on the finite element method is less than 8%. After determining the roughness coefficient under different rainfall conditions, the modified Peek formula can be applied to estimate the corona inception field strength of HVDC conductors under rainfall conditions, which is simple, accurate and easy to implement.关键词：roughness coefficient;corona inception field strength;Peek formula;raindrop;HVDC transmission9|3|0更新时间：2026-03-16
- 摘要：The ground-induced synthetic electric field beneath the high voltage DC line is susceptible to the influence of the structure of the line itself and the ambient wind speed，and the house beeanth the line has a distortion effect on the ground-induced synthetic electric field. Based on the above problems，a synthetic electric field numerical simulation model is proposed to explore the influence of above variables on the ground-induced synthetic electric field. The Comsol simulation is used to simulate and analyze the influence of line structure and wind speed on the ground-induced synthetic electric field and the distortion effect of the house structure beneath the line on the electric field. The analysis shows that in the line structure，the influence of the height from the condutor to the ground on the ground-induced synthetic field strength is maximum,and the influence of other line structures on the ground synthetic field strength is insignificant.In case of the wind speed less than 3 m/s，the ground field strength of the upwind side increases，however the ground field strength will decrease after the wind speed is greater than 3 m/s. Regarding the parameters of the houses beneath the line，the distortion effect of the height of the houses on the ground electric field distortion effect is maximum.In case identical net height of houses，the internal utilization space of the flat roof is large and the distortion of the top roof on the electric field is minimum.关键词：synthetic electric field;line structure;wind speed;house structure;COMSOL8|2|0更新时间：2026-03-16
- 摘要：The insulation structure of composite cross arms of EHV transmission lines is complex, and the electrical field distortion is serious in some important areas, the reasonable and effective configuration of grading shield device is an important link for ensuring to the safe and stable operation of the composite cross-arm tower. In order to determine the appearance structure and specific parameters of the grading shield device, a three-dimensional model of composite cross-arm is set up in this paper.Firstly, the electrical field distribution of the compound cross-arm without grading shield device is obtained by using simulation software, the electrical field distribution characteristics of the seriously distorted position are analyzed and the grading shield device is preliminarily designed. Then, the optimal Latin hypercube design method is adopted to extract the test sample points in the variable space of structural parameters of grading shield device, and the electrical field distribution on the surface of the composite cross-arm and the grading shield device under different sample points is obtained by finite element simulation. After that, by construct ing the Kriging model, the approximate model of the relationship between the field strength measured by the composite cross-arm and the grading shield device as well as the structural parameters of the grading shield device is built and, based on the sensitivity analysis technique, the influence of the structural parameters on the maximum field strength of the surface of the composite cross-arm and the uniform pressure shielding device is obtained. Finally, the optimal structure parameters of the grading shield device are obtained by theNSGA-Ⅱ.The results show that the field strength of composite cross-arm post insulator decreases by 63.5% and that of suspension insulator decreases by 54.7% when the grading shield device is installed, the surface field intensity of the composite cross-arm and the surface field intensity of the grading shield device can meet the control requirements.The optimization method can provide an important reference value for the optimal design of grading shield device of transmission lines.关键词：composite cross-arms;grading shield devices;multi-objective genetic algorithm;Kriging mode12|2|0更新时间：2026-03-16
- 摘要：Thyristor is the core component of converter valve. In recent years, the safety accidents of the equipment due to the aging of thyristor are increasing year by year. The safe operation of thyristor is related to the safe operation of converter valve and even the whole DC power transmission system. For studying the degradation characteristics of high voltage thyristors under steady-state temperature stress, a temperature accelerated stress degradation experiment scheme is designed firstly, the temperature accelerated stress degradation experiments for 1000 h at temperature of Tstg and 1.1Tstg are performed respectively on the basis of the platform, with a parameter measurement cycle of 100 h. The test data of characteristic parameters show that the temperature stress reduces the reverse recovery charge and trigger current of the thyristor to varying degrees, and the on-state voltage increases, while the leakage current changes suddenly without obvious forewarning. By analyzing the characteristics of aging elements, the main failure mode of the thyristor under temperature stress is reduction of withstanding voltage, and the migration of aluminum film on the surface of the chip are found.关键词：thyristor;acceleration stress;characteristic degradation;failure mode7|3|0更新时间：2026-03-16
- 摘要：For accurately identifying the fault of power module of VSC-HVDC converter valve and ensuring safe and stable operation of HVDC transmission, a thermal infrared image recognition method of power module of VSC-HVDC converter valve based on the temperature probability density is proposed. The target region of the thermal infrared image of the power module of theVSC-HVDCconverter valve is extracted by estimating the kernel density of the target constraint region and the background sampling region in the thermal infrared image.The temperature probability density is extracted based on the kernel density estimation and is used as the feature to distinguish the normal operation area and the fault area in the target area of the thermal infrared image. The fault area is preliminarily divided according to the threshold value in the target area of the thermal infrared image, and the preliminary division result is used as the prior knowledge of the K-means clustering algorithm. The purpose of fault identification is achieved bycontinuously clustering the fault area clusters. Experimental results show that the proposed method can accurately extract thermal infrared image targets by integrating the kernel density estimation of gray scale, spatial relationship and local standard deviation, and can accurately identify the fault location of the power module of theVSC-HVDCconverter valve.关键词：probability density;VSC-HVDC converter valve;power module;thermal infrared image;nuclear density estimation;K-means clustering algorithm12|3|0更新时间：2026-03-16
- 摘要：In view of the impact of access of inverter distributed generation (IIDG) on the traditional three-stage current protection of distribution network, the protection of distribution network including IIDG has received more and more attention. In this regard, an adaptive current protection scheme for distribution network with IIDG is proposed in this paper. In this paper, theoretical analysis is performed in accordance with the fault characteristics of IIDG and, in case of short circuit fault, the sequence network of the distribution network, and the refusal operation or mal-operation of the traditional three-stage current protection of the distribution network in case of access of IIDG are verified through simulation. An adaptive current protection scheme is proposed, which involves segmenting the output current of the pre-fault IIDG into intervals, performing iterative calculations for the communication and current protection devices, and then making the settings.The reliability of the distribution network adaptive current protection scheme with IIDG is verified by simulation. The setting calculation error of the proposed scheme is within the allowable error range, which greatly reduces the requirements for communication synchronization and communication volume, and is of great value to the application of adaptive current protection of distribution networks with IIDG.关键词：inverted interfaced distributed generator;distribution network;adaptive current protection;interval segmentation14|4|0更新时间：2026-03-16
Research & Analysis
- 摘要：For studying the influence of aging on electrode surface and arcing process, the aging experiments of plane electrode for vacuum on-load tap-changer are carried out in a demountable vacuum interrupter. The arcing image is taken by a high-speed camera, and the voltage and current waveforms are acquired by oscilloscope. The motion condition of cathode spot and arc voltage waveform under different aging are compared and analyzed. Experiment result show that with the conduction of aging, the contaminant on the electrode surface is removed gradually under the cleaning effect of cathode spots. The cathode spots are more stable in movement, the arc voltage is decreased and its fluctuation is reduced.关键词：vacuum on-load tap-changer;vacuum arc;current aging;arc voltage;cathode spot19|8|0更新时间：2026-03-16
- 摘要：For achieving reliable identification of operating status of power transformer in the on-site operating environment, a typical defect identification method of transformer based on robust local mean decomposition (RLMD) and voiceprint features is proposed. Firstly, the RLMD method is used to achieve noise reduction processing of the original collected voiceprint signal, and the sub-band components with strong correlation with the original voiceprint signal are retained with the Pearson correlation coefficient. Then, the voiceprint feature values of each sub-band component are extracted to form the feature parameter matrix of the transformer in different status. Finally, the random forest algorithm is used for status identification. A simulation system containing three typical faults of power transformer is set up, and the test results show that the proposed method realizes reliable characterization of power transformer in different working status, and the identification accuracy is improved by about 7%compared with conventional methods.关键词：transformer;robust local mean decomposition;voiceprint feature;defect identification11|4|0更新时间：2026-03-16
Technical Discussion
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